Formic Acid → 5-bromo-4-chloro-1H-benzoimidazole

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Reaction Steps

A mixture of 4-bromo-3-chloro-benzene-1,2-diamine (CASRN 1008361-80-5, 27 g, 0.1221 mol) and formic acid (80 mL) was heated to reflux for 1.5 h. After the completion of the reaction, 10% NaOH was added until the solution basic. The resulting solid was filtered and washed well with water then dried over night over suction to afford 22 g (78%) of 5-bromo-4-chloro-1H-benzoimidazole (128) as pale yellow solid which was used without additional purification.

Provenance & Evidence